Cosmetic I picked up joining ship (8)
I believe the answer is:
eyeliner
'cosmetic' is the definition.
(I know that eyeliner is a type of make-up)
'i picked up joining ship' is the wordplay.
'picked up' shows a homophone (sound like).
'joining' is a charade indicator (letters next to each other).
'ship' becomes 'liner' (liner is a kind of ship).
'i' is a homophone of 'eye'.
'eye'+'liner'='EYELINER'
(Other definitions for eyeliner that I've seen before include "kind of cosmetic" , "Facial cosmetic" , "Item of 25dn" , "instrument for enhancing lamps" , "it draws attention to the viewer" .)